Surgery is sometimes performed using an energy delivering system. Various types of therapeutic energies (e.g., electrical, RF, ultrasonic, microwave, cryogenic, heat, laser, etc.) may be used to treat a tissue. Electrosurgery is a tissue treating technique involving delivery of high RF electrical energy (e.g., 1-70 watts in bipolar and autobipolar electrosurgical systems, 1-300 watts in monopolar electrosurgical systems). Electrosurgical treatment is rendered by an electrosurgical system via an electrosurgical device (e.g., electrosurgical forceps, a treatment electrode and a dispersive neutral electrode (REM) pad). Electrosurgical RF generators differ widely in their output (energy carrier) RF, which may be approximately between 300 KHz and 480 KHz. There are three main types of electrosurgical systems: monopolar electrosurgical systems, bipolar electrosurgical systems and autobipolar electrosurgical systems.
Each electrosurgical system controls its operation state or mode (including transitioning between states and transitioning between operation modes) by using a feedback signal that is produced from electrical current samples and/or voltage samples that reflect, represent or are derived from the system's output RF energy. Controlling the state or operation mode of an electrosurgical system may include controlling an electrical parameter of the electrosurgical system, for example an electrical current that the electrosurgical system outputs, an electrical voltage that the electrosurgical system outputs or an electrical power of a therapeutic RF energy that the electrosurgical system outputs. Regardless of the type of the electrosurgical system that is used, using a reliable feedback signal is prerequisite to proper operation of the electrosurgical system, and thus to the RF treatment efficacy.
In some instances, conventional electrosurgical systems output therapeutic RF energy by using a same, or a similar, frequency. When two (or more) electrosurgical systems, which use a same, or a similar, carrier RF, treat two sites of a patient at a same time, it may occur that a therapeutic energy, when applied to one site by a first electrosurgical system, would interfere with the feedback signal of another electrosurgical system, and thus with the operation of the other electrosurgical system. One example scenario where two treatment sites are treated at the same time is a medical procedure known as coronary artery bypass grafting (“CABG”) which involves cardiac vein harvesting from the leg and implanting the harvested cardiac vein in another site where the vein is needed. In another scenario, a spine may be operated at two surgical sites by using two electrosurgical systems at a same time.
The interference an electrosurgical system may be subjected to is due to a remote therapeutic (high power) RF energy of another electrosurgical system that is superimposed on the feedback signal that is used to control the operation of the interfered with electrosurgical system. The feedback signal and an interfering therapeutic RF energy may jointly be subjected to constructive interference or to destructive interference, which makes the feedback signal susceptible to RF interferences that originate, for example, from other electrosurgical systems and have an identical, or similar, RF frequency. If the frequency of the feedback signal in one electrosurgical system and the frequency of the therapeutic RF energy are close (rather than being identical), alternating constructive interference and destructive interference may produce “beats” in the feedback signal, which would impair (distort, deform) the feedback signal, making it unreliable.
It would, therefore, be beneficial to have methods and system that enable simultaneous and independent operation of multiple electrosurgical systems without the electrosurgical systems interfering with one another during an electrosurgical procedure.